package org.letsgoyintong.springboot.common.interceptor;

import cn.hutool.core.util.StrUtil;
import com.auth0.jwt.JWT;
import com.auth0.jwt.JWTVerifier;
import com.auth0.jwt.algorithms.Algorithm;
import com.auth0.jwt.exceptions.JWTDecodeException;
import com.auth0.jwt.exceptions.JWTVerificationException;
import org.letsgoyintong.springboot.common.Constants;
import org.letsgoyintong.springboot.entity.User;
import org.letsgoyintong.springboot.exception.ServiceException;
import org.letsgoyintong.springboot.service.IUserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerInterceptor;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class JwtInterceptor implements HandlerInterceptor {

    @Autowired
    private IUserService userService;

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        String token = request.getHeader("token");
        // 如果不是映射到方法直接通过
        if(!(handler instanceof HandlerMethod)){
            return true;
        }
        if(StrUtil.isBlank(token)){
            //token为空 不符合条件
            throw new ServiceException(Constants.CODE_401, "无token，请重新登录");
        }
        String userId;
        try {
            userId = JWT.decode(token).getAudience().get(0);//这个就是封装在jwt里面的userId
        } catch (JWTDecodeException j) {
            throw new ServiceException(Constants.CODE_401, "token验证失败，请重新登录");
        }
        User user = userService.getById(userId);
        if(user == null){
            throw new ServiceException(Constants.CODE_401, "用户不存在，请重新登录");
        }
        // 验证 token
        JWTVerifier jwtVerifier = JWT.require(Algorithm.HMAC256(user.getPassword())).build();
        try {
            jwtVerifier.verify(token);//验证token
        } catch (JWTVerificationException e) {
            throw new ServiceException(Constants.CODE_401, "token验证失败，请重新登录");
        }
        return true;

    }
}
